Why Instant Electric Water Heaters Are Not Common in Canada: A Comprehensive Analysis

Canada, a vast and cold country, is known for its widespread availability of water heaters. However, why are there no common instant electric water heaters in Canada? In this article, we will explore the reasons behind this phenomenon, drawing upon the experience and analysis of the heating industry in other countries, such as the United Kingdom. We will also address common myths and misconceptions about these units.

Why Do People Not Use Instant Water Heaters in Some Regions?

If you believe that instant electric water heaters are not utilized due to a lack of sales in certain regions, you might be surprised to learn that they are used for showers in places like the United Kingdom. However, their limited use can be attributed to several physical constraints. Let's delve into the physics behind this phenomenon.

The Physics Behind Instant Water Heaters

Instant water heaters are designed to provide hot water on demand, but they come with significant limitations. The primary issue is the high heat capacity of water, which is a key factor in determining the energy required to heat it. Water has a specific heat capacity of 4.2 kJ per kg per degree Celsius, and this high value means it takes a substantial amount of energy to heat a given volume of water. In the context of household water systems, when water enters a home at 20°C and the hot water is at 60°C, there is a 40°C difference. To heat 1 kg of water by 40°C, 168 kJ of energy is required. If we consider a flow rate of 1 liter per second (1000 grams per second), the energy needed can be calculated as follows:

Energy (in Watts) MCp ΔT 1000 grams/s * 4.2 J/g°C * 40°C 168,000 Watts or 168 kW.

To supply this amount of energy at 240V voltage, the required current would be 168,000 / 240 700 Amps. This is far beyond the typical electrical capacity of a home. In the UK, the main fuse to a house is usually 100 Amps, making it impractical to power an instant water heater for an entire household.

How Instant Showers Work and Their Limitations

Despite the limitations mentioned above, instant showers are utilized in the UK, albeit with significant restrictions. These showers take water directly from the mains and provide a more manageable flow rate. For instance, a typical shower uses about 5-10 liters per minute, while instantaneous showers are rated at approximately 10 kW, drawing around 41 Amps. To install one of these showers, a separate electric feed is required from the mains, along with a substantial 10mm2 cable.

The flow rate of an instantaneous shower can be calculated as follows:

Flow Rate (liters per minute) 10 kW / (4.2 kJ/kg°C * 40°C) * 60 3.5 liters per minute.

This flow rate is indeed quite low, leading to a less than satisfactory shower experience. These limitations explain why instant water heaters are not commonly sold or used in Canada and other regions with similar conditions.

Conclusion

The choice not to sell instant electric water heaters in Canada is fundamentally rooted in physical limitations and practicality. While they are used for showers in the UK, the need for a substantial electrical supply and the low flow rate make them impractical for broader residential use. Understanding these challenges can help consumers and manufacturers make more informed decisions about the best type of water heater for their needs.

Frequently Asked Questions (FAQs)

Q: What are the main limitations of instant electric water heaters?

The primary limitations are the high heat capacity of water and the required electrical supply. Heating a large volume of water on demand requires a significant amount of energy, which is further compounded by the need for a large electrical connection.

Q: Can I use an instantaneous shower in my home?

While instantaneous showers are available, they are typically used for showers and have limited flow rates. They require a separate electric feed and a substantial cable due to the high power demand.

Q: Are there alternative options for efficient water heating?

Yes, there are alternative options such as tankless water heaters, which offer similar on-demand benefits but with more efficient energy usage and smaller physical footprints.

By understanding the limitations and practicality of instant electric water heaters, consumers can make informed decisions about the best water heating solution for their needs.